Medium power buck-boost circuits have traditionally relied on
transformers (SEPIC) or two cascaded DC/DC converters, one for the
step-up (boost) and one for the step-down (buck) conversion. The
LTC3785 requires only a single inductor from an input range of 2.7V
to 10V, offers an identical output range, and can deliver up to 50W
of output power. Operating with 4-switch synchronous rectification,
the LTC3785 provides seamless transitions between the buck and
boost operating modes.

The LTC3785's proprietary topology and control architecture
employs MOSFET RDS sensing for forward and reverse current
limiting, yielding unrivaled efficiency. A sense resistor may be
used when increased accuracy is desired. Moreover, the LTC3785
incorporates Burst Mode® operation which reduces light load
quiescent current to less than 100uA, a valuable feature in battery
powered systems. In addition, fault protection is provided for over
voltage, over current and short circuit conditions in all operating
modes. The operating frequency can be programmed from 100kHz to
1MHz with a single resistor and the LTC3785 also incorporates true
output disconnect during shutdown.

The LTC3785 is offered in a 4mm x 4mm QFN-24 package. The
1,000-piece price is $3.56 each.

Summary of Features: LTC3785

•

Single Inductor Architecture Allows Operation with the
Input Voltage Above, Below or Equal to the Output Voltage